An antenna is typically used to capture electromagnetic energy to a receiver when used in a receive mode, and, conversely radiates electromagnetic energy from a transmitter when used in a transmit mode. To achieve this, the antenna needs to be properly positioned. For example, U.S. Pat. No. 6,937,199 to King discloses a parabolic reflector antenna that includes two-axis mechanical scan for positioning the antenna. Azimuthal scanning is provided by a turntable and elevational scanning is provided by an elevation assembly and positioner. In addition, the parabolic reflector has a truncated lower edge to reduce its vertical profile.
A group of related U.S. Pat. Nos. 6,653,981 and 6,657,589, and U.S. Published Application Nos. 2003/0083063; 2003/0080907; 2003/0080898 all to Wang et al. discloses a low profile cylindrical reflector antenna system. The system includes a pair of cylindrical reflector antennas that are scanned in the azimuth direction by a turntable, and in the elevational direction by an elevation assembly and positioner.
A low profile antenna system may be particularly desirable for airborne applications, for example. A particularly advantageous low profile antenna system is disclosed in U.S. Pat. No. 6,204,823 to Spano et al. and assigned to the assignee of the present invention. The patent discloses a phased array antenna with two-axis mechanical scanning. Azimuthal scan is provided by a turntable, and elevational scan is provided by an elevation drive mechanism. Similarly, U.S. Pat. No. 5,952,980 to Boling discloses a low profile antenna positioning system that may include a reflector antenna.
Unfortunately, the conventional low profile reflector antenna positioning systems may still be too large for a number of applications, such as particularly for airborne applications, and hybrid or phased array antennas may add unwanted complexity and cost.